There's no doubt CrossFit brings big results. The real question: Is it safe? Sixteen percent of folks in an Ohio State University study dropped out of a 10-week CrossFit program due to overuse or injury. "All too often participants jump right in without understanding what they're doing, which ups their injury risk," says celeb trainer Yumi Lee Mathews, owner of Reebok CrossFit LAB in L.A. Here's how to hurt less—and benefit more.
2. Find a good coach
Look for an instructor who has training beyond just a CrossFit level-one certification, Mathews says—think ACSM or ACE certified. Also important: She should be able to break down and teach each movement before you perform it and answer any questions you may have, plus offer modifications as well as safe weight recommendations.
3. Know your limits
"If you feel faint, light-headed, dizzy, nauseous or unable to catch your breath or are in any pain whatsoever," Mathews says, "stop immediately and talk to your coach."